1. Field of the Invention
The present invention relates generally to a hand tool, and more particularly to a hand tool with adjustable swing angle.
2. Description of the Related Art
The applicant's U.S. Pat. No. 7,987,749 discloses a wrench with a rotatable head as shown in FIGS. 1 and 2. The wrench with the rotatable head includes a handle 10 and at least one head section 11 pivotally connected with the handle 10 via an engagement pin 14. Accordingly, the relative angle contained between the handle 10 and the head section 11 is adjustable. One end of the handle 10 has an upper wall section 12 and a lower wall section 13 spaced from each other by a certain distance. The upper wall section 12 is formed with a first splined hole 121 and the lower wall section 13 is formed with a through hole 131. A restriction flange 132 is formed on a wall face of the through hole 131. The head section 11 extends into a space between the upper and lower wall sections 12, 13. The head section 11 has a second splined hole 111 positioned between the first splined hole 121 and the through hole 131. The engagement pin 14 is up and down movably mounted in the first and second splined holes 121, 111.
An annular groove 141 is formed on a circumference of the engagement pin 14. A C-shaped retainer 142 is disposed in the annular groove 141. The C-shaped retainer 142 has an outer diameter larger than an inner diameter of the second splined hole 111 of the head section 11. Several springs 143 and steel balls 144 are embedded in a bottom end of the engagement pin 14. When the engagement pin is positioned in an engagement position as shown in FIG. 2, the engagement pin 14 is engaged with both the first and second splined holes 121, 111. In this case, the angle contained between the handle 10 and the head section 11 is fixed. Under such circumstance, the C-shaped retainer 142 abuts against a bottom face of the second splined hole 111 to prevent the engagement pin 14 from upward detaching out of the first and second splined holes 121, 111. The steel balls 144 abut against a top face of the restriction flange 132 to keep the engagement pin 14 in the engagement position. When adjusting the relative angle contained between the handle 10 and the head section 11, the engagement pin 14 is moved downward to a release position (not shown), whereby the engagement pin 14 is disengaged from the first splined hole 121, permitting the handle 10 and the head section 11 to rotate relative to each other. At this time, the steel balls 144 pass over the restriction flange 132 to be positioned under the restriction flange 132, whereby the engagement pin 14 is kept in the release position. The C-shaped retainer 142 abuts against the restriction flange 132 to avoid detachment of the engagement pin 14.
The above mechanism for locating the engagement pin 14 and avoiding detachment of the engagement pin 14 is complicated and includes numerous components and is thus hard to manufacture. For example, it is necessary to drill holes on the engagement pin 14 for manually installing the springs 143 and the steel balls 144 into the holes. In addition, it is necessary to form the annular groove 141 on the engagement pin 14 for receiving the C-shaped retainer 142.